Thanks again. Yes, perhaps I'll avoid the integrated solution - a pain if the driver packs up too.

The nominal torque of the original motors is 300 oz in which is 2.1Nm - the machine's manual states the "maximum holding moment" as 3.2Nm.

I found this data sheet on line - https://drive.google.com/file/d/0Bxr...ew?usp=sharing

Thanks for the Leadshine observation. The Nema34 Leadshine motors are only two phase.